A novel fragmentation-aware spectrum allocation algorithm in flexible bandwidth optical networks

Flexible bandwidth optical networking (FBON) based on optical orthogonal frequency-division multiplexing (O-OFDM) technology has been proposed to accommodate traffic over 100 Gb/s in the future due to its flexibility in spectrum allocation. In FBON, due to the limit of spectrum continuity constraints (SCC), routing and spectrum allocation (RSA) suffers a lot from spectrum fragments. Therefore, a lot of schemes have been proposed to deal with spectrum fragmentation, including spectrum conversion, spectrum sweeping retuning, multi-path routing, and fragmentation-aware RSA algorithm. These schemes are carefully designed to lower blocking probability. However, they usually need extra/high-quality infrastructures, require complex processing, or cause traffic interruption. To reduce spectrum fragmentation, we investigate spectrum allocation approach through utilizing the relationship between spectrum blocks' accommodation capability and traffic bandwidth distribution. Based on this, a fragmentation-aware spectrum allocation (FSA) algorithm is presented. Generally, this algorithm probabilistically optimizes the spectrum resource allocation process. The simulation results show that it is able to achieve a lower bandwidth blocking probability.